Dies are used in the prior art to shape, form, draw and notch metal or other suitable material and these prior prior art dies are generally affixed to a die set which is a two-piece devise that is in turn attached to a punch press. The die set typically consists of a steel top plate and a steel bottom plate aligned with one another by means of guide posts and bushings permitting vertical movement of the top plate relative to the bottom plate but preventing relative lateral movement therebetween. The die set includes a bottom die shoe containing guide posts and a top punch shoe containing guide bushings. The punch holder or top punch shoe is affixed to the punch press ram and the die holder or bottom die shoe is affixed to the bolster plate of the press.
Useful work is accomplished with die sets by bolting and dowel pinning various tools e.g., punch blocks or punch retainers and die blocks or die button retainers to both the bottom and top shoes of die sets. Normally, die blocks or die button retainers are aligned on the bottom shoe first. This is usually accomplished by affixing a straight edge or parallel to the edges of the guide pins on the bottom shoe and then placing a square against the straight edge or parallel and one of the guide posts establishing both parallel and perpendicular reference planes. After the reference planes have been established, placing gage blocks against the straight edge and the square provides rectangular coordinates corresponding to the edges of the guide posts. Die blocks to be mounted are placed against the gage blocks and transfer punches are used to transfer the bolt hole pattern to the bottom shoe. Using those punch marks the bottom shoe is drilled and tapped for mounting bolts.
Although the setting of the die blocks or die button retainers is a relatively easy procedure its main disadvantage is that its difficult to affix the straight edge, position the square, gage blocks and die blocks or die button retainers in such a manner as to insure that nothing has moved. My invention greatly reduces the possibility of misalignment and it is a faster and easier method and apparatus to use than prior art procedures.
The real problems in die assembly arise when trying to align punch block or punch retainers to correspond with the die blocks. This procedure in the past has proved to be extremely difficult and time consuming. My invention provides a novel structural arrangement and a novel method of aligning punch and die tooling to overcome the objections of the prior art procedures.
In the past, the prior art teaches us that it was a common practice to reach into the die set and align the punch blocks or the punch retainers with the die blocks then insert a scribing tool into the screw-receiving openings in the punch blocks and scribe circles on the under surface of the punch. The top shoe or punch shoe was then removed and mounting holes drilled and tapped. A great improvement over this method of mounting punch blocks or punch retainers was attained in the Whistler Patent U.S. Pat. No. 3,126,776, whereby e spotting and transfer means was used to provide visible markings on the other shoe for drilling, tapping and mounting of punch retainers. Magnetic inserts have been tried for positioning purposes as was taught and claimed in U.S. Pat. Nos. 3,089,376, and 3,782,166. Adhesives have been used for mounting purposes as was taught and claimed in U.S. Pat. No. 3,504,576. And, fixtures or tooling plates have been used to secure punch and die retainers as taught and claimed in U.S. Pat. Nos. 4,359,915 and 2,504,642.
All previous methods and apparatuses used for mounting punch and die button retainers are deficient in that in order to transfer bolt hole patterns from the, punch retainers to the die shoe, either it was necessary to have the top and bottom shoes assembled together or an individual fixture machined for different dies.